TWI619895B - Flat strain wave gearing - Google Patents

Abstract

A flat-type harmonic gear device (1) is provided with a mechanism for preventing a flexible external gear (4) from facing a rigid internal gear (2, 3) and moving in the direction of the central axis (1a) of the device. The mechanism includes: an inner circumferential groove (11) formed in the inner teeth (3a) of the internal gear (3); an outer circumferential groove (12) formed in the outer teeth (4a) of the outer gear (4); A flexible ring portion (13) between the groove (11) and the peripheral groove (12). The ring portion (13) can be engaged with the inner circumferential side surface (11a, 11b, 12a, 12b) of the groove from the direction of the device's central axis (1a) at the meshing position of the two gears (2, 4).

Description

Flat type harmonic gear device

The present invention relates to a flat-type harmonic gear device, comprising: two rigid gears; and a cylindrical flexible gear, which is bent by a harmonic generator in a radial direction and is respectively Partially meshed with 2 rigid gears.

Such a flat-type harmonic gear device is best known as having two rigid internal gears and a cylindrical flexible external gear disposed inside the two internal gears. When the flat-type harmonic gear device is in operation, a thrust is generated between the two gears due to the meshing of the internal gear and the external gear, and the external gear moves in the direction of the central axis of the device. That is, regardless of whether the two gears are flat gears with a helix angle of 0 ° at the same time, thrust will be generated due to the walking phenomenon unique to the meshing of the harmonic gear device.

As shown in FIG. 6, in a general flat-type harmonic gear device 100, an internal gear 102 on one side is fixed to the casing 101 so as not to rotate, and an internal gear 103 on the other side is freely rotatable. The mode is supported on the casing 101. The internal gear 103 and the external gear 104 are integrated While spinning. The harmonic generator 105 is rotationally driven by the motor 106, and the rotation of the internal gear 103 is output from an output shaft 107 coaxially fixed to the internal gear 103. During the deceleration operation, a thrust force is generated toward the fixed-side internal gear 102 side, and during an accelerated operation, the thrust force is conversely generated toward the rotating-side internal gear 103 side.

In order to restrict the movement toward the device central axis 100a when subjected to a thrust force, skew prevention portions 108 and 109 (in the figure, portions surrounded by a single-point lock line) are provided on both sides of the external gear 104 to restrict this movement. In addition, when the external gear 104 moves toward the center axis 100a of the device, the thrust force acting on the external gear 104 is the maximum, which is about 3 to 4 times the thrust force when the external gear 104 hits the skew prevention portion 108 or 109 and stops.

In the flat-type harmonic gear device described in Patent Documents 1 and 2, restricting members are provided on both sides of the external gear so that the external gear does not move in the axial direction due to thrust.

[Prior technical literature] [Patent Literature]

[Patent Document 1] JP 2011-110976

[Patent Document 2] JP 2013-177938

In the flat type harmonic gear device, in order to limit the external gear When the device is moved toward the center axis of the device and distorted portions or restricting members are disposed on both sides thereof, the size of the device increases and the cost increases. In addition, if anti-skewing parts or restricting members are provided on both sides of the center axis direction of the device of the external gear, lubricant may be prevented from flowing through both sides of the external gear to the meshing portion of the two gears. As a result, disadvantages such as an increase in the friction amount of the meshing portion due to insufficient lubrication may occur.

In view of this, an object of the present invention is to provide a flat-type harmonic gear device which does not include members such as an anti-skew portion and a restricting member on both sides in the center axis direction of the device of the flexible gear, but includes A mechanism that restricts the movement of a flexible gear.

The flat-type harmonic gear device of the present invention includes: a first rigid gear; a second rigid gear arranged coaxially next to the first rigid gear; and a coaxial rigid arrangement of the first and second rigid gears. A cylindrical flexible gear on the outer or inner peripheral side; a harmonic generator that bends the flexible gear into a non-circular shape, and locally meshes with the first and first parts respectively 2 rigid gears, and the meshing position is moved in the circumferential direction; the first groove formed in the tooth portion of the first rigid gear is formed over the entire circumference; and the first groove is opposed to the first groove and formed in the flexibility throughout the entire circumference. A second groove of the tooth portion of the gear; and a first ring portion which is arranged between the first and second grooves and can be bent in a radial direction. The first ring portion can be formed between the first rigid gear and the flexible portion. The meshing positions of the linear gears are respectively engaged with the groove inner peripheral surfaces of the first and second grooves from the direction along the center axis of the device.

In the present invention, the mechanism for preventing the flexible gear from facing the first rigid gear and moving in the direction of the central axis of the device is formed by a first groove formed in a tooth portion of the first rigid gear and a flexible gear The second groove of the tooth portion and the first ring portion are formed.

When the flexible gear faces the first rigid gear and moves toward the center axis of the device, the second groove on the flexible gear side also faces the first groove on the first rigid gear and moves in the same direction. The first ring portion attached to the first and second grooves is engaged at the meshing position of the two gears, and is engaged with the inner peripheral surface of the groove of the first groove on one side of the center axis direction of the device, and is engaged with the other side. The inner peripheral surface of the second groove. Therefore, the first ring portion can function as a member for restricting the movement of the flexible gear. Therefore, it is not necessary to arrange members for restricting the movement of the flexible gear on both sides, and the flexible gear can be restricted from moving toward the first rigid gear.

In a general flat-type harmonic gear device, the number of teeth of the first rigid gear is the same as that of the flexible gear, the number of teeth of the second rigid gear is greater than the number of teeth of the first rigid gear, and the second The rigid gear train is fixed to a device housing or the like in a non-rotating manner.

At this time, once the harmonic generator is rotated, the flexible The flexible gear rotates relative to the second rigid gear according to the difference in the number of teeth, and the first rigid gear rotates integrally with the flexible gear. The first ring portion mounted between these gears also rotates substantially integrally with these gears. Therefore, it is possible to suppress the occurrence of a loss such as a reduction in the performance of the harmonic gear device, and to restrict the movement of the flexible gear.

In the present invention, the first groove is formed from an end portion of the second rigid gear side of the first rigid gear toward a center axis of the device, and a distance of 1/2 from a tooth width of the first rigid gear. The above position is better.

In the meshing area between the first and second rigid gears and the flexible gear, the first and second grooves are arranged at positions separated from the center in the tooth width direction toward the outside. In this way, it is possible to reduce the effects of increasing the tooth surface stress caused by the meshing of the two gears due to the installation of the first and second grooves.

Here, the half of the difference between the outer diameter and the inner diameter of the first ring portion may be set to be the same or smaller than the tooth height of the flexible gear.

Next, a ring portion may be disposed between the second rigid gear and the flexible gear. At this time, in addition to the above-mentioned configuration, the flat-type harmonic gear device of the present invention is provided with a third groove formed on the tooth portion of the second rigid gear throughout the entire circumference; A fourth groove is formed circumferentially in the tooth portion of the flexible gear, and a flexible second ring portion is disposed between the third and fourth grooves. The second ring portion is arranged at a meshing position between the second rigid gear and the flexible gear. It can be engaged with the inner peripheral surface of the groove of the said 3rd and 4th groove from the direction along the center axis of a device, respectively.

In this case, the third groove is formed at a distance 1 / from the end of the second rigid gear on the first rigid gear side toward the center axis of the device, from the tooth width 1 / of the second rigid gear. A position of 2 or more is preferred.

The difference between the outer diameter and the inner diameter of the second ring portion is preferably ½ of the same or smaller than the tooth height of the flexible gear.

Next, in a typical flat-type harmonic gear device to which the present invention is applied, the first rigid gear train is a first internal gear; the second rigid gear is a second internal gear; and the flexible gear is an external gear; The harmonic generator is configured to bend the external gear into an oval shape, and the external gear is meshed with the first and second internal gears at both ends of the long axis of the ellipse, and the number of teeth of the first internal gear is the same For the number of teeth of the external gear, when n is a positive integer, the number of teeth of the second internal gear is 2n more than the number of teeth of the first internal gear, and the second internal gear is fixed so as not to rotate. Each time the wave generator rotates, the external gear will rotate the second internal gear only with a difference in the number of teeth, and the first internal gear will rotate integrally with the external gear.

Even in this case, the first groove is formed from the end of the second internal gear of the first internal gear toward the center axis of the device, away from the teeth of the first internal gear. A position of 1/2 or more is preferable.

In addition, the inner diameter of the first ring portion is formed on the outer teeth with and The diameter of the groove bottom of the second groove of the wheel is preferably the same, so that the first ring portion and the external gear are integrated and bent into an oval shape.

In addition, the groove bottom diameter of the second groove is preferably larger than the diameter of the tooth bottom circle of the external gear, so as to prevent the thickness of the tooth bottom ring of the flexible gear from becoming thin due to the setting of the second groove, resulting in teeth Decline in fatigue strength.

Furthermore, the diameter of the groove bottom of the first groove formed in the first internal gear is preferably larger than the outer diameter of the long axis position of the first ring portion bent into an ellipse, so as to avoid the At both ends of the oval long axis at the meshing position, the outer peripheral surface of the first ring portion that is bent into an oval shape affects the first internal gear.

In this case, it is only necessary to set 1/2 of the difference between the outer diameter and the inner diameter of the first ring portion in advance to be equal to or smaller than the tooth height of the first internal gear or the external gear.

The first ring portion has a high rigidity in the center axis direction, is easy to bend in the radial direction, and is easy to be narrowed in the radial direction as a whole, and it is preferable that it can be widened. As the first ring portion having such characteristics, a ring formed by a skew coil spring can be used. In addition, a ring formed by winding a leaf spring in a spiral shape, a ring formed by an endless belt spring, or a corrugated ring formed by bending a leaf spring in a corrugated shape can also be used.

1‧‧‧ flat harmonic gear device

1a‧‧‧ device center axis

2‧‧‧ Internal gear (1st rigid gear, 1st internal gear)

2a‧‧‧Inner teeth

3‧‧‧ Internal gear (second rigid gear, second internal gear)

3a‧‧‧Inner teeth

4‧‧‧External gear (flexible gear)

4a‧‧‧outer teeth

5‧‧‧ Harmonic generator

11‧‧‧ Inner ditch (No. 1 ditch)

11a, 11b

12‧‧‧ Peripheral groove (second groove)

12a, 12b

13‧‧‧Ring (Ring 1)

21‧‧‧Inner ditch (3rd ditch)

22‧‧‧ Peripheral groove (4th groove)

23‧‧‧Ring (Ring 2)

30‧‧‧ Flat Harmonic Gear Device

32‧‧‧1st external gear

32a‧‧‧The first external tooth

33‧‧‧ 2nd external gear

33a‧‧‧The second external tooth

34‧‧‧ Internal gear

34a, 34b‧‧‧ Internal tooth

34c‧‧‧ cylindrical body

35‧‧‧Harmonic generator

35a‧‧‧plug

35b‧‧‧Harmonic generator bearing

[Fig. 1] (a) shows a flat type harmonic gear device to which the present invention is applied (B) is its front view.

[Fig. 2] (a) is a partially enlarged longitudinal sectional view showing a partially enlarged part of the flat-type harmonic gear device of Fig. 1, and (b) is an explanatory diagram showing a mounting portion of a ring portion.

[Fig. 3] (a) is an explanatory diagram showing a mounting portion of the ring portion, and (b) is an explanatory diagram showing a cross-sectional shape of the first and second grooves.

[Fig. 4] (a) and (b) are explanatory diagrams showing characteristics required for the ring portion, and (c) and (d) are explanatory diagrams showing the ring portion.

[Fig. 5] (a) is a semi-vertical cross-sectional view showing another example of the flat-type harmonic gear device to which the present invention can be applied, and (b) is a semi-front view thereof.

6 is a schematic longitudinal sectional view showing a conventional flat-type harmonic gear device.

Hereinafter, embodiments of the flat-type harmonic gear device to which the present invention is applied will be described with reference to the drawings.

Fig. 1 (a) is a longitudinal sectional view showing a flat-type harmonic gear device according to this embodiment, and Fig. 1 (b) is a front view thereof. The flat-type harmonic gear device 1 includes an internal gear 2 that is a fixed side of a rigid gear and an internal gear 3 that is an output side (rotation side); a cylindrical external gear 4 that is a flexible gear; and a harmonic generator. 5.

The internal gears 2 and 3 are spaced slightly apart, and are arranged coaxially in the direction of the device central axis 1a. The external gear 4 is coaxially disposed inside the internal gears 2 and 3. External gear 4 series has: contains internal gear Tooth width of 2,3. The external teeth 4a of the external gear 4 face the internal teeth 2a of the internal gear 2 on one side, and the other teeth face the internal teeth 3a of the internal gear 3 on the other side.

The harmonic generator 5 bends the external gear 4 into a non-circular shape. In this example, the external gear 4 is bent into an oval shape, and it is meshed with the internal gears 2 and 3 at the position of the long axis L of the oval shape. . When the harmonic generator 5 rotates, the meshing position between the external gear 4 and the internal gears 2 and 3 also moves in the circumferential direction.

For example, the number of teeth of the internal gear 3 on the output side is 2n less than the number of teeth of the internal gear 2 on the fixed side (n is a positive integer). The number of teeth of the internal gear 3 and the external gear 4 is the same. During the first rotation of the harmonic generator 5, the external gear 4 rotates the internal gear 2 on the fixed side relative to the angle corresponding to the difference in the number of teeth. The internal gear 3 on the output side is rotated integrally with the external gear 4. The rotation system of the internal gear 3 is output toward a load member side (not shown).

FIG. 2 (a) is a partially enlarged longitudinal sectional view showing a part of the flat-type harmonic gear device 1 in an enlarged manner, and FIG. 2 (b) is an explanatory view showing a further enlarged part of FIG. 2 (a).

As shown in these drawings, an inner peripheral groove 11 (a first groove) is formed in a portion of the inner teeth 3a of the inner gear 3 on the output side and opens toward the inside. The inner circumferential groove 11 is a direction orthogonal to the tooth width direction of the inner teeth 3a, and is formed over the entire circumference of the inner teeth 3a. The outer teeth 4a of the outer gear 4 also have a peripheral groove 12 (a second groove) that is open to the outside and is formed on the portion facing the internal groove 11. Inner peripheral groove 11 and outer peripheral groove 12 Between them, a flexible ring portion 13 that can be bent in a radial direction is attached. The ring portion 13 has a circular cross section.

FIG. 3 (a) is an explanatory diagram showing the inner circumferential groove 11, the outer circumferential groove 12, and the ring portion 13, and FIG. 3 (b) is an explanatory diagram showing the cross-sectional shapes of the inner circumferential groove 11 and the outer circumferential groove 12. The inner peripheral groove 11, the outer peripheral groove 12, and the ring portion 13 will be described in more detail with reference to FIGS. 2 and 3.

The cross-sectional shape and groove bottom diameter of the inner peripheral groove 11 and the outer peripheral groove 12 and the cross-sectional shape and size of the ring portion 13 are appropriately set as described below. In addition, at the meshing position of the internal gear 3 and the external gear 4, that is, at the position of the long axis, the ring portion 13 can be engaged with the inner peripheral groove 11 and the outer peripheral groove 12 from the direction along the central axis 1a of the device, respectively. The left and right groove inner peripheral sides 11a, 11b, 12a, 12b.

In this example, the inner circumferential groove 11 is a groove with a rectangular cross section, and the groove width is the same or only slightly larger than the diameter d of the ring portion 13. In addition, the inner circumferential groove 11 is formed from the end of the internal gear 2 on the other side of the internal gear 3 toward the center axis 1a (see FIG. 1) of the internal gear 3, away from the tooth width W1 / of the internal gear 3 2 or more from the distance L1. For example: it is formed about 2/3 away. The position outside the center of the tooth width direction is less affected by the tooth surface stress caused by the meshing of the two gears 3 and 4. Therefore, it is possible to minimize the disadvantages of forming the inner peripheral groove 11 and the outer peripheral groove 12 and greatly increasing the tooth surface stress of the two gears 3 and 4.

Next, the inner diameter Di (13) of the ring portion 13 is approximately the same as the groove bottom diameter D (12) formed in the peripheral groove 12 of the outer gear 4 so that the ring portion 13 can be integrated with the outer gear 4 and bent. Fold into oval. In addition, the diameter d of the circular contour of the ring portion 13, that is, 1/2 of the difference between the outer diameter Do (13) and the inner diameter Di (13), is set to be the same or only slightly smaller than the teeth of the external gear 4. High L (4a).

On the other hand, the outer circumferential groove 12 on the side of the external gear 4 is a groove having a semi-circular cross section, and the groove width at the open end is the same or only slightly larger than the diameter d of the ring portion 13. By forming a semicircular groove, stress concentration can be reduced, and a decrease in the fatigue strength of the tooth bottom can be suppressed. The diameter D (12) of the groove bottom of the outer circumferential groove 12 is set to be slightly larger than the tooth bottom circle diameter D (4a) of the external gear 4. By using the peripheral groove 12 of the arc-shaped cross section, the stress concentration caused by the cross-section defect can be alleviated, and the decrease in the fatigue strength of the tooth bottom can be suppressed.

In addition, the groove bottom diameter D (11) of the inner circumferential groove 11 on the inner gear 3 side is set to be larger than the outer diameter of the long axis position of the flexible ring portion 13 that can be bent into an ellipse. In this way, at the meshing position of the two gears 3 and 4 (both ends of the long axis), the outer peripheral surface portion of the flexible ring portion 13 that is bent into an oval shape will not affect the side of the internal gear 3 .

4 (a) and 4 (b) are explanatory diagrams showing characteristics required of the ring portion 13. As shown in FIG. 4 (a), the ring portion 13 requires high axial rigidity. By doing so, the movement of the external gear 4 can be reliably restricted.

As shown in FIG. 4 (b), the ring portion 13 needs to be easily bent toward its radial direction. When the ring portion 13 is mounted on the peripheral groove 12, it can be formed into an oval shape along the groove bottom. Furthermore, the ring portion 13 also needs to be able to be narrowed to an average small diameter from its outer peripheral side by the force acting on the inner side in the radial direction, and from its inner peripheral side by acting on The force on the outside in the radial direction is easy to be widened to an average large diameter. In this way, the ring portion 13 can be easily assembled.

As the ring portion 13 having such characteristics, a ring formed by winding a leaf spring into a spiral shape can be used. Alternatively, a leaf spring formed by connecting both ends of a tightly wound coil spring ring may be used. Further, as shown in FIG. 4 (c), a leaf spring having a fixed width can be bent into a corrugated shape to form a ring-shaped corrugated ring. Furthermore, as shown in FIG. 4 (d), it is preferable to use a ring portion constituted by an oblique coil spring. In addition to these rings, any ring having the above characteristics can be used.

Further, the ring portion 13 may be attached between the inner peripheral groove 11 of the internal gear 3 and the outer peripheral groove 12 of the external gear 4 in the following order. First, the ring portion 13 is widened and attached to the outer circumferential groove 12 of the externally-toothed gear 4. The external gear 4 on which the ring portion 13 is mounted is further mounted inside the internal gears 2 and 3.

At this time, the outer diameter of the ring portion 13 mounted on the external gear 4 and the crown circles of the internal gears 2 and 3 only partially overlap. Since the ring portion 13 has elasticity that can be narrowed toward the inside in the radial direction, the ring portion 13 can be elastically deformed to mount the external gear 4 inside the internal gears 2 and 3. When the external gear 4 is mounted on the internal gears 2 and 3, the ring portion 13 is placed between the external circumferential groove 12 of the external gear 4 and the internal circumferential groove 11 of the internal gear 3.

Then, the harmonic generator 5 is mounted on the inner peripheral surface of the external gear 4. As a result, the external gear 4 is bent into an oval shape, and the two gears are engaged with the internal gears 2 and 3 at both ends of the long axis. As shown in Figures 2 and 3, At the meshing position of the external gear 4 and the internal gear 3, the ring portion 13 can be engaged with the inner circumferential grooves 11a, 11b, 12a, and 12b of the inner circumferential groove 11 and the outer circumferential groove 12 from the direction of the device central axis 1a. .

When the flat-type harmonic gear device 1 configured as described above is in operation, the external gear 4 moves toward the center axis 1a of the device due to the thrust generated by the meshing of the internal gears 2, 3 and the external gear 4. The engagement of the ring portion 13 with the groove inner peripheral side surfaces 11a, 11b, 12a, 12b is restricted.

For example, as shown in FIG. 3 (a), when the external gear 4 moves in the direction of arrow A1, the groove inner peripheral side surface 11b of the inner peripheral groove 11 and the groove inner peripheral side surface 12a of the outer peripheral groove 12 will relatively approach toward the ring portion 13, The ring portion 13 is pressed from both sides. Although the internal gear 3 is supported to be rotatable freely, it is still restricted from moving toward the device central axis 1a.

Therefore, the external gear 4 passes through the groove inner peripheral side surface 12 a of the outer peripheral groove 12, the ring portion 13, and the groove inner peripheral side surface 11 b of the inner peripheral groove 11, is engaged with the inner gear 3 side, and is restricted from being moved in the direction of the arrow A1. Similarly, the external gear 4 is also restricted in that it cannot move in the opposite direction (the direction of the arrow A2).

In order to restrict the movement of the external gear 4, it is not necessary to arrange restriction members on both sides in the direction of the center axis 1 a of the device. Therefore, the supply path of the lubricant to the meshing portions of the external gear 4 and the internal gears 2 and 3 can be secured through both sides of the external gear 4. As shown in FIG. 6, when the skew preventing portions of the restricting member are arranged on both sides of the external gear, friction is liable to occur due to insufficient lubrication of the meshing portion, but in this example, such friction can be prevented from occurring. Raw.

(Modification)

In the above-mentioned flat-type harmonic gear device 1, a mechanism (inner peripheral groove 11, outer peripheral groove 12, ring portion 13) for restricting the movement of the external gear 4 is provided between the internal gear 3 and the external gear 4 on the output side. ). In addition, the same mechanism may be provided between the internal gear 2 and the external gear 4 on the fixed side of the other side.

At this time, as shown by a virtual line in FIG. 2 (a), the inner circumferential groove 21 is formed on the inner teeth 2 a of the inner gear 2 over the entire circumference. On the other hand, at the position facing the inner circumferential groove 21, the outer circumferential groove 22 is formed in the outer gear 4 over the entire circumference. Between these inner peripheral groove 21 and outer peripheral groove 22, a flexible ring portion 23 is attached.

Even in this case, the inner circumferential groove 21 is preferably formed at a position at a distance of 1/2 or more from the tooth width from the end portion on the inner gear 3 side. The dimensions of each of the inner circumferential groove 21, the outer circumferential groove 22, and the ring portion 23 are preferably set to be the same as the relationship between the inner circumferential groove 11, the outer circumferential groove 12, and the ring portion 13 described above.

In this case, a relative rotation corresponding to the difference in the number of teeth occurs between the internal gear 2 and the external gear 4 on the fixed side. The contact area between the inner circumferential groove 21 of the rectangular cross section of the internal gear 2 and the flexible ring portion 23 of the circular cross section is reduced (see FIG. 3). Therefore, the sliding frictional force occurring between the ring gear 2 and the ring portion 23 becomes small.

(Other embodiments)

FIG. 5 (a) is a half cross-sectional view showing an example of a flat-type harmonic gear device having another configuration to which the present invention can be applied, and FIG. 5 (b) is a half front view thereof. The flat-type harmonic gear device 30 shown in these figures includes: a first external gear 32 and a second external gear 33 of a rigid gear; and a cylindrical flexible gear arranged coaxially outside the gears. An internal gear 34; and a harmonic generator 35 embedded on the outer side of the internal gear 34.

The internal gear 34 includes a cylindrical cylindrical portion 34c that can be bent in a radial direction, and internal teeth 34a and 34b formed on a circular inner peripheral surface of the cylindrical cylindrical portion 34c. The internal teeth 34 a and 34 b are external teeth 32 a and 33 a that can be engaged with the first and second external gears 32 and 33.

The harmonic generator 35 is composed of: a rigid plug 35a having an oval inner peripheral surface and a fixed thickness; and a pair of harmonic generator bearings 35b mounted on the oval inner peripheral surface of the plug 35a. The harmonic generator bearing 35b as a whole is bent into an elliptical shape along the elliptical inner peripheral surface of the plug 35a. Therefore, the internal gear 34 is also bent into an elliptical shape along the elliptical inner peripheral surface of the plug 35a, and the internal teeth 34a and 34b at the short diameter position are engaged with the first and second external gears 32 and 33, respectively. The first and second external teeth 32a and 33a. When the harmonic generator 35 rotates, the meshing positions between the internal gear 34 and the first and second external gears 32 and 33 will move in the circumferential direction, respectively.

The flat-type harmonic gear device 30 having such a configuration includes an outer peripheral groove 41, an inner peripheral groove 42, and a ring portion 43 for restricting the movement of the internal gear 34 between the first external gear 32 and the internal gear 34. Similarly, in Between the second external gear 33 and the internal gear 34, an outer peripheral groove, an inner peripheral groove, and a ring portion for restricting the movement of the internal gear 34 may be disposed.

Claims (12)

A flat-type harmonic gear device comprising: a first rigid gear; a second rigid gear arranged coaxially next to the first rigid gear; and a coaxial rigid arrangement on an outer peripheral side of the first and second rigid gears Or a cylindrical flexible gear on the inner peripheral side; a harmonic generator that bends the flexible gear into a non-circular shape, and locally meshes with the first and second rigidities, respectively A gear, and the meshing position is moved in a circumferential direction; a first groove formed in the tooth portion of the first rigid gear over the entire circumference; and a first groove formed opposite to the first groove, formed in the flexible gear over the entire circumference. A second groove of the tooth portion; and a first ring portion which is arranged between the first and second grooves and can be bent in a radial direction. The first ring portion can be formed between the first rigid gear and the flexible gear. The meshing positions are engaged with the groove inner peripheral surfaces of the first and second grooves from the direction along the center axis of the device. According to the flat type harmonic gear device described in the first item of the patent application scope, the number of teeth of the first rigid gear is the same as the number of teeth of the flexible gear, and the number of teeth of the second rigid gear is more than the above. Number of teeth of the first rigid gear, The second rigid gear is fixed so as not to rotate. When the harmonic generator rotates, the flexible gear will rotate relative to the second rigid gear according to the difference in the number of teeth. The first rigid gear will The flexible gear rotates integrally. The flat-type harmonic gear device according to item 1 of the patent application scope, wherein the first groove system is formed in a direction from an end portion on the second rigid gear side of the first rigid gear toward a center axis of the device. , At a distance of 1/2 or more from the tooth width of the first rigid gear. The flat-type harmonic gear device according to item 1 of the scope of patent application, wherein the difference between the outer diameter and the inner diameter of the first ring portion is 1/2 of the same or less than the tooth height of the flexible gear. . The flat-type harmonic gear device according to item 1 of the scope of the patent application, further comprising: a third groove formed on a tooth portion of the second rigid gear over the entire circumference; and a third groove formed across the entire periphery of the third groove. A fourth groove is formed circumferentially in the tooth portion of the flexible gear; and a second ring portion which is arranged between the third and fourth grooves and can be bent in a radial direction, and the second ring portion can be formed in The meshing positions of the second rigid gear and the flexible gear are respectively engaged with the groove inner peripheral surfaces of the third and fourth grooves from the direction along the center axis of the device. The flat-type harmonic gear device according to item 5 of the patent application scope, wherein the third groove system is formed in a direction from an end portion on the first rigid gear side of the second rigid gear toward a center axis of the device. , At a distance of 1/2 or more from the tooth width of the second rigid gear. The flat-type harmonic gear device according to item 5 of the scope of patent application, wherein the difference between the outer diameter and the inner diameter of the second ring portion is 1/2 or less than that of the second rigid gear or the The teeth of the flexible gear are high. The flat-type harmonic gear device according to item 1 of the scope of patent application, wherein the first rigid gear train is a first internal gear, the second rigid gear train is a second internal gear, and the flexible gear train is In the external gear, the harmonic generator bends the external gear into an ellipse, and engages the external gear with the first and second internal gears at both ends of the long axis of the ellipse, and the first internal gear The number of teeth is the same as the number of teeth of the external gear. When n is a positive integer, the number of teeth of the second internal gear is 2n more than the number of teeth of the first internal gear. The second internal gear is fixed so as not to rotate. For each revolution of the harmonic generator, the external gear will rotate the second internal gear only with a difference in the number of teeth, and the first internal gear will rotate integrally with the external gear. The flat-type harmonic gear device according to item 8 of the scope of patent application, wherein the first groove system is formed in a direction from an end portion on the second internal gear side of the first internal gear toward a center axis of the device. , At a distance of 1/2 or more from the tooth width of the first internal gear. The flat-type harmonic gear device according to item 8 of the scope of patent application, wherein the inner diameter of the first ring portion is the same as the diameter of the groove bottom of the second groove formed in the external gear, and the second The diameter of the groove bottom of the groove is larger than the circle diameter of the tooth bottom of the external gear before being bent into an ellipse, and the diameter of the groove bottom of the first groove formed in the first internal gear is larger than that of the groove being bent into an ellipse The long diameter of the first ring portion is shaped. The flat-type harmonic gear device according to item 10 of the scope of the patent application, wherein the difference between the outer diameter and the inner diameter of the first ring portion is 1/2 of the tooth height of the external gear. The flat-type harmonic gear device according to item 11 in the scope of the patent application, wherein the first ring portion is: a ring formed by winding a leaf spring into a spiral shape; or a ring formed by an annular belt spring; Or a corrugated ring formed by bending a leaf spring into a corrugated shape; or a ring formed by an oblique coil spring.